A Guide to SCP: Secure File Transfer on Ubuntu

SCP command examples

Before using the scp command, you should understand its basic syntax.

The scp command syntax uses the following format:

scp [OPTION] [user@]SRC_HOST:]file1 [user@]DEST_HOST:]file2

• OPTION – scp options that specify cipher, SSH configuration, SSH port, limit, recursive copy, etc.
• [user@]SRC_HOST:]file1 – path to the source file.
• [user@]DEST_HOST:]:file2 – path to the destination file.

Local files can be specified using an absolute or relative path, while remote file names must include a user and host specification.

The most commonly used options for the SCP command are:

• -P – Specifies the remote host ssh port.
• -p – Preserves file modification and access times.
• -q – Use this option to suppress the progress meter and non-error messages.
• -C – This option forces scp to compress the data as it is sent to the destination machine.
• -r – This option tells scp you to copy directories recursively.

Transferring files

To transfer a file from the local machine to a remote machine, use the following command:

scp [options] /path/to/local/file username@remote:/path/to/destination

For example, to transfer a file named `example.txt` from the local machine to a remote machine with the IP address `192.168.0.2`, use the following command:

scp example.txt username@192.168.0.2:/home/username/

To transfer a file from a remote machine to the local machine, use the following command:

scp [options] username@remote:/path/to/file /path/to/destination

For example, to transfer a file named `example.txt` from a remote machine with the IP address `192.168.0.2` to the local machine, use the following command:

scp username@192.168.0.2:/home/username/example.txt /home/localuser/

If you want to save the file under a different name, specify the new file name at the destination. If SSH on the remote host is listening on a port other than the default 22, then you can specify the port using the -P argument:

scp -P 2322 example.txt username@192.168.0.2:/home/username/newName.txt

Transferring directories

To transfer a directory from the local machine to a remote machine, use the following command:

scp [options] -r /path/to/local/directory username@remote:/path/to/destination

For example, to transfer a directory named `example` from the local machine to a remote machine with the IP address `192.168.0.2`, use the following command:

scp -r example/ username@192.168.0.2:/home/username/

To transfer a directory from a remote machine to the local machine, use the following command:

scp [options] -r username@remote:/path/to/directory /path/to/destination

For example, to transfer a directory named `example` from a remote machine with the IP address `192.168.0.2` to the local machine, use the following command:

scp -r username@192.168.0.2:/home/username/example/ /home/localuser/

That should do it!

Conclusion:

• Using the SSH protocol, SCP (secure copy) is an essential command-line utility for securely transferring files and directories between networked devices.
• It provides a secure way to transfer files over a network and is particularly useful for protecting sensitive information on insecure networks.
• Understanding the SCP command’s basic syntax and commonly used options is crucial for efficient usage.
• The examples demonstrate transferring files and directories between local and remote machines using SCP on Ubuntu Linux.